For organic light-emitting diodes, efficient conversion of electrical charges to light is a critical process. When two changes or opposite sign (cations and anions) combine on a emitter molecule they can give excited states with different electron spin configurations. Most often the electron spins are aligned represents a triplet state and for purely organic materials these materials generally are only weakly emissive because the radiative transition to the ground state requires a forbidden spin transition. Singlet states can also be produced and are more strongly emissive with allowed radiative transitions to the ground state. To fully transform all of the excited states into luminance from a device, materials which facilitate interconversion of triplet states into singlet states are desired.